Our son started dual credit in 10th grade (we had homeschooled before that) and he graduated with his AA this year, he was in 12th grade.
He did not have a high school diploma, but earned high school as well as college credits for the work, and it is noted on his transcript that he earned a high school diploma from homeschool (I did have to submit a transcript and just included all the courses he had taken at the college .... he had 78 hours in the three years and needs 51 to complete his major.)
He's entering the state university in the fall as a junior, and we had no problem at all with his acceptance, even though he doesn't have a traditional high school diploma. Also had no problem getting full tuition scholarship, and the dual credit in our state is free, so it makes for a very low cost way to send your kid to college (we did have to pay for books.)
There are 2 guys like that in my Calculus class.
The guys are frikin brilliant. Both want to be Engineers.
There is hope.